Ideally calves should promptly receive 5-6% of body weight in clean, high-quality maternal colostrum. Unfortunately, opposing factors may prevent this from happening. Many farms have limited availability of employees and/or managers to oversee that colostrum is promptly and properly collected and fed to newborn calves. Missed management steps often result in failure of passive transfer (FPT) and increased illness early in the calves life. Insufficient volume, low quality, and presence of disease such as Johne’s or leukosis can also make it difficult to ensure the calf is receiving enough passive immunity from the first meal of colostrum.
In situations where enough clean high-quality colostrum is not available, or in situations where employees may struggle in processing colostrum in a clean and timely manner, farms may turn to feeding a colostrum replacer as the first meal, instead of maternal colostrum.
Colostrum Supplement vs. Colostrum Replacer
Any product that is capable of raising the blood serum IgG concentration above 10 mg/ml can be called a colostrum replacer. Products unable to raise the blood serum IgG above the species standard of 10 mg/ml, are called colostrum supplements. In the U.S. all colostrum products containing IgG are regulated by the USDA Center for Veterinary Biologics.
Colostrum supplements contain 40 to 60 IgG per dose (9-13% globulin protein), 0.5-15% fat, and are typically made from dried bovine colostrum or serum. Colostrum supplements can be used to increase the IgG content of low or medium quality colostrum. Unfortunately, research has shown that IgG are often poorly absorbed when using a colostrum supplement. Poor antibody absorption may be due to a large portion of protein entering the intestine in a short amount of time. It has been suggested that perhaps IgG and other proteins compete for absorption sites.
Colostrum replacers were developed because supplements were not very effective, and because using a supplement added to maternal colostrum will not break a disease cycle as some maternal colostrum will still be fed to the calf. Colostrum replacer products are made from bovine colostrum or serum and contain 100 to 150 grams of IgG per dose. These products also contain protein, fat, vitamins, and mineral essential to the newborn calf.
Choosing a Quality Product
When choosing a colostrum supplement or replacer it is important to not only consider the IgG concentration, but also the absorption efficiency. The amount of IgG provided and the efficiency at which the IgG are absorbed varies significantly from product to product. There are three primary sources of IgG used in colostrum products; dried colostrum, bovine serum, and eggs. Most supplements contain 30-45% IgG or protein, and when fed according the manufacturer’s directions, provide 45-50 mg/ml of IgG per dose.
Supplement and replacer products made from bovine serum contain high levels of IgG and have absorption efficiencies of 25-35%, similar to maternal colostrum. Products based on colostrum or whey ingredients have variable concentrations of IgG and absorption efficiencies range from 5-30%. Egg based supplements typically are not as well absorbed and have mostly been replaced by colostrum and serum ingredients. However, egg-based additives can be beneficial in providing local protection in the intestine against scours causing bacteria.
Whether you are supplementing low quality colostrum, or using a replacer, it is important for the calf to receive at least 100 g of IgG in the first feeding. Verify effectiveness of the product you choose by monitoring success of passive transfer in your calves. And of course always follow manufacturer’s instructions for mixing and feeding to ensure the best possible results for healthy calves!
Written by: Mariah Gull, M.S.